Mobile crane



July 29, 1952 T. GRAVES 2,605,002

MOBILE CRANE Filed March 1, 1948 3 Sheets-Sheet l INVENTOR.

L/ 010 7/14/0300 'raue s ATTORN E L. T. GRAVES MOBILE CRANE July 29,1952 Filed March 1, 1948 3 Sheets-Sheet 2 INVEN TOR. 670066 Lloyd Harman ATTORN EY y 29, 1952 T. GRAVES 7 2,605,002

- MOBILE CRANE Filed March 1, 1948 3 Sheets-Sheet 3 25 K} INVENTORPatented July 29, 1952 MOBILE CRANE Lloyd Thurman Graves, NorthVancouver, British Columbia, Canada, assignor, by direct and mesneassignments, of two-thirds to William Blaylock Steele, Vancouver,British Columbia,

Canada Application March 1, 1948, Serial No. 12,262

9 Claims.

This invention relates to improvements in mobile cranes, and for itsgeneral object aims to provide a load-handling machine of this characterassuring exceptional maneuverability, simplicity of control, andapplicability to a wide range of work requirements.

More particularly stated, it is one object of the present invention todevise a mobile crane employing a cantilever arm for its boom and havingthe fulcrum and power points so located as to give to the boom thesubstantial working characteristics of a lever of the third order.

As a further object still, the invention aims to provide a mobile cranepeculiarized in that the point to which power is applied for raising orlowering the working end of the boom is guidably held to movement alonga perpendicular axis fixedin relation to the vehicular support, and inwhich the fulcrum, in compensation of the power points rectilinealmovement, is linked to the vehicular support in a manner permitting thefulcrum to float within a localized swing arc.

The invention has the yet further aim, and which is ancillary to theafore-mentioned object, of devising a mobile crane utilizing hydraulicenergy as the force responsible for swinging the boom, and having, asthe functioning instrumentality therefor, a piston-and-cylinder assemblycharacterized in that the cylinder is made rigid with the frame of thesupporting vehicle.

It isa yet further objectto provide a mobile crane in which the armwhich links the fulcrum to the vehicular support is adjustable forlength.

The invention has the further and important object of providing a boomcomprised of telescoping sections and which, in its permitted adjustmentof the length orreach of the boom, works in complement with the verticaladjustment of the fulcrum point to most easily adapt the crane tovarying requirements of different load-handling operations.

Other still more particular objects and advantages will, with theforegoing, appear and be understood in the course of the followingdescription and claims, the invention consisting in the novelconstruction and in the adaptation and combination of parts hereinafterdescribed and claimed.

In the accompanying drawings:

Figure 1 is a fragmentary side elevational view portraying a mobilecrane constructed to embody the preferred teachings of the presentinvention. Fig. 2 is a somewhat similar view taken to an enlarged scalewith parts broken away and shown in section, and also illustrating thefulcrum as having been adjusted to occupy a lower level than that inwhich it is portrayed in Fig. 1.

Fig. 3 is a horizontal sectional view on line 3-3 of Fig. 2.

Fig. 4 is a front elevational view of the vehicle and its boom-carryingtower, and showing the boom in transverse vertical section. v

Fig. 5 is a top plan view portraying the-boom and the head end of thetower, and with the boom broken away and shown partly in section; and

Fig. 6 is a view diagramming the hydraulic circuit.

Referring to said drawings, the self-propelled wheeled vehicle whichgives mobility to the crane is designated generally'by the numeral l0,said vehicle having its engine located at the rear end and beingsteerable through the rear wheels. In order to simplify the drawings andinsofar as the vehicle is concerned, I have confined the illus trationto a portrayal of only the front wheels I I together with so much of thechassis as permits a showing of the driver's seat 12 and the variouscontrols for the operation of both the vehicle and the crane.

According to the present invention there is placed at the front end ofthe vehicle and integrated with the frame thereof a tower comprised of apair of opposingly placed uprights l3 and I4 lying one at one side andthe other at the other side of the vehicles longitudinal median line andhaving a respective channel member, as I5 and it, welded or otherwiserigidly secured thereto to extend upwardly as a perpendicularprolongation of the upright. These channel members are disposed tolocate their gutters in facing relation. For reinforcing the channelshorizontal sets of ribs I! and [8 are applied externally thereof atspaced intervals of the height, and the tower members are braced fromthe frame by diagonal struts 20. The lower said set of ribs spans thetower to produce a rigid tie between the channel members.

Associated with said rigid channel members is an inner sliding frameworksimilarly composed of a pair of transversely spaced'channel membersdesignated 2| and 22 and which, likewise, are placed with the gutters infacing relation, and made integral with these sliding channels andplaced adjacent the head end thereof is a reinforced cross-tie 23.Employed to elevate said inner frame-work is a hydraulic ram 24 findingrigid connection by its head end against the underside of thecross-tiaand as the complement of this ram there is provided a cylinder25 which foots upon and is made rigid with the frame of the vehicle. Thefluid circuit for the ram is or may be conventional and is shownschematically in Fig. 6, comprising a continuously driven pump 26drawing oil through a pipe 21 from a reservoir 28 and operating by meansof a control valve 29 to force this oil through either of two pipes 30or 3| into the cylinder or back to the reservoir, selectively, the valvebeing of a three-way character to also allow pressure oil within thecylinder to be bled back to the reservoir. Incorporated in the circuitis a by-pass pipe 32 fitted with a pressure-release valve 33 and leadingfrom the output side of the pump to the return pipe 30.

Reverting to the movable inner element of the telescoping tower, thereis welded within the gutters of each of the channel members 2| and 22 tolie at the head ends thereof and above the cross-tie 23 a respectiveblock 34 which acts in complement with a cap 35 to form bearings for atransverse pivot pin 36, and receiving a journal mounting from this pinis a hollow boom comprised of a root section 31 and a reach section 33,the reach section, in order to admit of telescoping action in respect ofthe root section, receiving a slide journal within the latter. The pointat which said root section is journaled upon the pivot pin is proximateto but forwardly removed from the rear extremity of the root section,and attached by a transverse pivot pin 4| to the rearwardly projectingheel 40 is a muff 42 serving as a floating fulcrum for the boom. Thismuff sleeves upon and is attached by a pin 43 to the head end of avertical stay-link 45, and the bottom and of said stay-link connectswith the frame of the vehicle by an anchor pin 46. For adjusting theswing radius of the fulcrum pin tithe muff and the link each provide aseries of alternatively employed holes, as 41 and 48, arranged to bebrought into selective registration for reception of the pin 43. Asimilar instrumentality is used for setting the boom arm to adjustedlengths, and namely a pin 50 insertable through the root section 3'7into a selected one of several holes 51 piercing opposite side walls ofthe reach section at spaced intervals of the latters length. In theinstance of both pins, the same present threads upon one end which workin the threads of a nut or nuts 52 welded upon the back face of the rootsection 31 or the muff 42, as the case may be; and to facilitateapplication of these pins the same are provided upon the other end witha handle.

There is journal-mounted at both the front andrear ends of the boom arespective sheave, as 54 and 55, and passing from a power drum 56located at the base of the tower over the rear sheave 55and thencethrough the hollow center of the boom along the length of the latter toand over the sheave 54 is a cable 51 fitted upon its free end with ahook 58. Powering the drum through worm and worm-wheel gearing carriedin a case 69 which also serves as one of the cheek bearings for the drumis a shaft 81 driven from the engine of the vehicle and controlled by aforward-andreverse transmission 62.

The root section of the boom has provided upon its underside a fitting63 which is placed, by preference, immediately forward of the tower, andthis fitting, as indicated by dotted lines in Fig. l, accommodates theattachment of the hook. When so attached, and subject only to a loweringof the boom such that, its outer end lies 'oelow the pivot pin 36, theoperator may, by removing the pin 50, lengthen or shorten the boom byeither slacking off or taking up on the cable. The

4 greased guide-way in which the reach section is slidably journaledallows the reach section to move freely, wherefor force of gravityserves to lengthen the boom while a pull force exerted by the bight ofthe cable to the sheave 54 shortens the boom. For adjusting the lengthof the link, the operator need only hook the endof the cable in thefitting 63, withdraw the pin 43, and then take up or slacken off on thecable, the boom then swinging about the pivot pin 36 as a fulcrum, thepin 43 being replaced when the desired holes of the muff and link arebrought into registration.

.As will, it is believed, be clear, the boom operates as a lever of thethird order in that the same is fulcrumed at the rear extremity and hasits power applied at a point intermediate the ends. This feature isimportant in point of its desirable load distribution. However, whileeminently to be preferred over an arrangement in which, say, the fulcrumwould be located forward rather than to the rear of the lower point, thelatter arrangement is deemed to be within the teachings of the inventionto the end that it would still permit the employment of a floatingfulcrum and hence allow the applied power, albeit working in a counterdirection, to be passed into the boom along a fixed perpendicular axis.The invention and the manner of its operation is thought to be apparentfrom the foregoing detailed description of my now-preferred embodiment.I am cognizant that a re-location of parts such as I have referred toabove, as well as minor changes in the details of construction, may beresorted to without departing from the spirit of the invention and Itherefore intend that the hereto annexed claims be read with thebroadest interpretation to which the employed language fairly admits.

What I claim, is:

1. A load-handling vehicle comprising, in combination with the vehicleframe, a tower structure rigid with said vehicle frame, a lift membercarried by the tower for vertical sliding movements in relation thereto,means for raising and lowering the lift member, an extensible boomcomprising a root section and a reach section receiving a slide journalfrom the root section, said root section being fulcrumed to the frame ofthe vehicle and being pivotally connected with the lift member at apoint longitudinally offset from the fulcrum, respective sheaves carriedby the boom sections at the forward and rear ends of the boom, 2.power-driven drum carried by the vehicle frame, a cable presenting ahook upon its free end and running from the drum over the rearwardlyplaced sheave and therefrom to and over the forwardly placed sheave, afitting upon the root section of the boom arranged to be engaged by thehook and operating by the act of lowering the boom and coincidentlytaking up or slacking off on the cable to adjustably slide the reachsection in relation to the root section and thereby either shorten orlengthen the boom, and means for securing the two sections in selectedadjusted positions.

2. A load-handling vehicle comprising, in combination with the vehicleframe, a tower structure rigid with said frame, a lift member carried bythe tower for vertical sliding movements in relation thereto,,means forraising and lowering the lift member, an upright link located to therear of the tower and having an anchoring pivot at its lower end, a mudsleeved for endwise movement upon the link and having means for-securingthe same in selected adjusted positions thereon, and a boom fulcrumed byits rear extremity to the muif and receiving a pivot mounting from thelift member at a point forwardly removed from the fulcrum.

3. The load-handling vehicle of claim 2 in which the means for securingthe muif and link in adjusted positions comprises a series of holespiercing the link at spaced intervals of the length and a second seriesof holes provided by the muff and arranged to be brought selectivelyinto register with a selected one of the first said series, and alocking pin arranged to be passed through said registering holes of thetwo series.

4. In a load-handling vehicle, and in combination with the vehicleframe, a tower structure made rigid with the vehicle frame and providinga pair of channel members placed one in facing relation to the other atopposite sides of the longitudinal median line of the vehicle, a unitarymovable frame-work providing paired channel members receiving a slidejournal within the gutters of the rigid channel members, a hydrauliccylinder rigidly supported by the vehicle frame to occupy a positionbelow the movable frame-work, a ram working in the cylinder andconnected by its head end with the movable frame-work, a pressure sourceof hydraulic fluid for the cylinder-and-ram assembly, an upright linklocated to the rear of the tower and having an anchoring pivot at itslower end, and a boom fulcrumed by its rear extremity to the upper endof said link and pivotally connected to the movable frame-work at apoint forwardly removed from the fulcrum.

5. In a load-handling vehicle, and in combination with the vehicleframe, a tower structure made rigid with the vehicle frame and providinga pair of channel members placed one in facing relation to the other atopposite sides of the longitudinal median line of the vehicle, a unitarymovable frame-work providing paired channel members receiving a slidejournal within the gutters of the rigid channel members, a hydraulichoist contained within the tower structure and providing a cylinderfooting upon the frame of the vehicle and a ram working in the cylinderand exerting its lift thrust upon the movable framework, a source ofhydraulic pressure for said hydraulic hoist, a link disposed to the rearof the tower and pivotally anchored to the frame of the vehicle forlongitudinal swinging movement about a transverse axis, a hollow boomfulcrumed by its rear end to the free end of said link and pivoted tothe movable frame-work at a point forwardly removed from said fulcrum,sheaves carried by the boom at the front and rear ends thereof, apower-driven drum located at the foot of the tower structure, and acable runnin from the drum to the rearwardly placed sheave and passingtherefrom through the hollow center of the boom to and over theforwardly placed sheave.

6. In a load-handling vehicle, and in combination with the vehicleframe, a tower structure made rigid with the vehicle frame, said towerstructure comprising a pair of channel members placed one in facingrelation to the other at opposite sides of the longitudinal median lineof the vehicle and having said members connected by a yoke and eachreinforced at the back sides by a diagonal strut, a unitary movableframe-work providing paired channel members receiving a slide journalwithin the gutters of the rigid chan-- nel members, power meansoperatively connected with said movable frame-work and supported by thevehicle frame for raising and lowering said movable frame-work, and aboom fulcrumed to the frame of the vehicle and having a pivotalconnection with the head end of the movable framework at a pointlongitudinally offset from said fulcrum.

7. The load-handling structure of claim 6 in which the boom isextensible and is comprised of telescoping root and reach sections withthe root section being a double-walled structure of which the inner walldefines a sleeve closely fitting the reach section and guiding thelatter in its endwise movement relative to the root section.

8. A load-handling vehicle comprising, in combination with the vehicleframe, a tower structure rigid with said vehicle frame, a lift membercarried by the tower for vertical sliding movements in relation thereto,means for raising and lower ing the lift member, and an extensible boomcomprised of telescoping root and reach sections of which the rootsection is fulcrumed to the frame of the vehicle and pivotally connectedwith the lift member at a point longitudinally offset from the fulcrum,said reach section having a substantially uniform cross-sectional sizefrom the inner end thereof throughout very nearly its entire length,said root section being a double-walled structure of which the outerwall flares outwardly from the outer toward the inner end of suchsection and of which the inner wall defines a sleeve closely fitting thereach section and guiding the latter in its endwise movement relative tothe root section.

9. A load-handling vehicle comprising, in combination with the vehicleframe, a tower structure rigid with said vehicle frame, a lift membercarried by the tower for vertical sliding movements in relation thereto,means for raising and lowering the lift member, an extensible boomcomprising a root section and a reach section receiving a slide journalfrom the root section, said root section being fulcrumed to the frame ofthe vehicle and being pivotally connected with the lift member at apoint longitudinally offset from the fulcrum, respective sheaves carriedby the boom sections at the forward and rear ends of the boom, apower-driven drum carried by the vehicle frame, a cable presenting ahook upon its free end and running from the drum over the rearwardlyplaced sheave and therefrom to and over the for- Wardly placed sheave, afitting occupying a position in proximity of and localized with respectto the root section's axis arranged to be engaged by the hook andoperating by the act of lowering the boom and coincidently taking up orslacking off on the cable to adjustably slide the reach section inrelation to the root section and thereby either shorten or lengthen theboom, and means for securing the two sections in selected adjustedpositions.

LLOYD 'I'HURMAN GRAVES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 795,524 Leffmann July 25, 19051,540,135 Klinkhammer June 2, 1925 1,917,053 Nelson et al. July 4, 19332,208,221 McCullough July 16, 1940 2,392,004 Sherman Jan. 1, 19462,445,614 Flynn et al July 20, 1948 2,506,242 Shoemaker May 2, 1950

